Icebox ruin: RoroCo glove factory (#92473)

## About The Pull Request

Adds a new surface ruin to icebox, the RoroCo factory. Contains a couple
of puzzles, and a small amount of loot in the form of ~~3 total pairs of
insulated gloves~~ a pair of insulated gloves, two adorable roros and a
cool unique labcoat. Just don't ask where the gloves come from...

Puzzles can of course be avoided/brute-forced by breaking down the walls
but that's for chumps.

<img width="1152" height="1024" alt="Space Station 13 2025-08-06 221903"
src="https://github.com/user-attachments/assets/21050aa6-9b27-494d-a949-7496aeda18cf"
/>

## Why It's Good For The Game

The upcoming 1x3 icebox surface calls for more ruin content to help fill
that space.

## Changelog
🆑
add: A new insulated glove factory has popped up on the ice moon.
add: Freezer floor tiles now come in the full range of shapes.
/🆑

code/game/objects/structures/billboard.dm

@@ -104,3 +104,8 @@
 	name = "\improper All-American Diner billboard"
 	desc = "A billboard advertising an old-school 1950's themed restaurant franchise \"All-American Diner\""
 	icon_state = "billboard_american_diner"
+
+/obj/structure/billboard/gloves
+	name = "\improper RoroCo Gloves billboard"
+	desc = "A billboard advertising RoroCo, a manufacturer of insulated gloves and insulated glove accessories. Features the company's loveable mascot Roro."
+	icon_state = "billboard_gloves"